1. Field of the Invention
The present invention relates to a method for manufacturing an electronic component module that is suitable for manufacturing an electromagnetically readable data carrier operating as an aircraft tag, a physical distribution management label or an unmanned wicket pass, and more particularly to a method for manufacturing an electronic component module in which a semiconductor bear chip is packaged on a wiring board by a flip chip connecting method at low cost, in which it is possible to prevent a short circuit from occurring due to a contact of the semiconductor bear chip with an electrode area on the wiring board even under a situation where a high temperature and high pressure load is applied on a packaged portion of the semiconductor bear chip.
2. Description of the Related Art
A so-called “aircraft tag” is well known as the electromagnetically readable data carrier of this type. It is expected that this aircraft tag is used in disposable manner for the management of customer luggage at the airport in the near future. There will be a great demand of 8,500,000 tags per month only in one company in the case of an aircraft company on a worldwide scale. Therefore, it is desired that a mass production technology is established with very low cost for the aircraft tag of this kind.
For example, an aircraft tag is well known in which a vortex conductor pattern serving as an antenna coil and the IC parts for a transmitting and receiving circuit and a memory are mounted on one face of a PET film substrate having a rectangular shape. In this aircraft tag, an aircraft tag main body holding the vortex conductor pattern serving as the antenna coil is formed by selectively etching a copper foil or aluminum foil attached on one face of the PET film. Therefore, a continuous production line based on the RTR (Roll To Roll) is easily realized through a resist formation process by a well-known photolithography technique and a subsequent wet etching process. On the other hand, the circuit parts serving as a transmitting and receiving circuit and a memory, which are packaged on the aircraft tag main body, are constructed in one chip, employing a semiconductor integration technique (e.g., refer to patent document 1).
The present applicant has previously offered a technique in which a semiconductor bear chip composing a transmitting and receiving circuit and a memory is packaged in advance on a film-like insulating wafer (a kind of wiring board) to make a module. This electronic component module is bonded onto a PET film composing the aircraft tag main body to increase the productivity of the aircraft tag (refer to document patent 2).
For an electronic parts mounting sheet requiring a high degree of thinness such as the electronic component module bonded on the aircraft tag, various proposals have been made regarding a flip chip connecting method for directly mounting a semiconductor bear chip on the wiring board.
FIG. 17 shows one example of the flip chip connecting method (hereinafter referred to as a first method of the related art). With this first method, a protruding terminal b (referred to as a bump) for connection is formed beforehand on a bottom electrode (not shown) of the semiconductor bear chip, and the bump b and an electrode area (scheduled connection area with the bump b) d on a wiring pattern of the wiring board c are aligned, and connected by a bonding material e such as solder or conductive paste.
The first method has several problems that (1) a process for supplying and curing the bonding material e for connecting the bump b and the electrode area d on the wiring pattern is complex, (2) a process for filling an insulating resin f called an under-fill between the chip a and the wiring board c and sealing a bump connecting portion is required to obtain a reliable moisture resistance of the bump connecting portion and a mounting strength of semiconductor, and (3) a process for filling and curing the insulating resin f as the under-fill is needed, thereby increasing the manufacturing cost.
FIG. 18 shows another example of the flip chip connecting method (hereinafter referred to as a second method of the related art). The second method solves the problems associated with the first method. The second method involves packaging a semiconductor bear chip on the wiring board employing an anisotropic conductive sheet. In the second method, an anisotropic conductive sheet g having conductive particles dispersed in the thermoplastic or thermosetting resin is interposed between the semiconductor bear chip a and the wiring board c. The electrical connection in the thickness direction is made with conductive particles h between the bump b and the electrode area d on the wiring pattern by flowing the resin owing to thermocompression bonding (e.g., refer to patent document 3).
In the second method, the alignment with the wiring pattern is relatively roughly made in packaging the semiconductor on the wiring board. The resin curing time is as short as 10 to 20 seconds. There is no need for using the sealant such as under-fill. Therefore, the manufacturing cost is reduced. On the contrary, there are still several problems that (1) the anisotropic conductive sheet g is relatively expensive, (2) the temperature higher than 200° C. is required for curing to disable the less heat-resistant board, (3) it takes 10 to 20 seconds to cure the resin material, though it is a relatively short time. It is difficult to simplify and make faster the process, and (4) the electrical connection between the bump and the wiring pattern is made by the contact of conductive particles dispersed in the resin material, with poor reliability of connection.
Thus, the present applicant has offered a flip chip connecting method (referred to as a third method of the related art). FIGS. 19A-19C show the flip chip connecting method according to the third method. With this third method, a semiconductor bear chip a formed with the bump b of semicircular section is packaged on a flip chip connecting wiring board having the wiring board c, the electrode area d on the wiring pattern formed on the wiring board c, and a thermoplastic resin film (resin adhesive) i covering the electrode area d.
More specifically, there are a process for positioning (positioning process) the bear chip a side (bump b) and the wiring board c (electrode area d)(FIG. 19A), a process for contacting (removal process of thermoplastic resin film) the bump b and the electrode area d by pressing the conductive bear chip a downward (arrow direction in FIG. 19B) to partly shove away the melted thermoplastic resin film i while applying ultrasonic wave to the bump b in a state where the thermoplastic resin film i is heated employing a heater table (FIG. 19B), a process for ultrasonically bonding (metal melting) (process of ultrasonic bonding) the bump b and the electrode area d by further applying ultrasonic wave continually in a state where the bump b and the electrode area d are contacted (FIG. 19C), and a process for bonding the semiconductor bear chip main body on the wiring board by cooling and solidifying the melted thermoplastic resin film (not shown) (refer to patent document 4).
With this third method, a series of packaging processes, including melting the thermoplastic resin film i, bonding the bump b and the electrode area d by applying ultrasonic wave to the bump b, and curing (cooling and solidifying) the thermoplastic resin film i, are performed within one to two seconds, whereby the manufacturing time is shortened. Owing to the metal melting bonding between the bump b and the electrode area d, the electrical connection has a reliability.
However, this third conventional method has the following problems.
FIGS. 20A-20B show an example of a method for working a card and a token included in the data carrier with the semiconductor bear chip mounted. FIG. 20A shows a method for working the card included in the data carrier by a laminate press. FIG. 20B shows a method for working the token included in the data carrier by injection molding. More specifically, with the working method as shown in FIG. 20A, the data carrier main body k with the semiconductor bear chip j mounted is sandwiched between two resin films 1-1, and in this state, pressed by a pair of metal plates m-m heated to a temperature of about 120° C. vertically with a pressure of 100 to 200 Kg/cm2 to integrally bond two films 1-1 and the data carrier, whereby the card included in the data carrier is produced. With the working method as shown in FIG. 20B, the data carrier main body k with the semiconductor bear chip j mounted is disposed at a predetermined position within an inner cavity of a mold n, and in this state, a resin having a temperature of 250° C. is injected from a resin inlet hole p of the mold n under the pressure of 40 to 80 Kg/mm2, whereby the token included in the data carrier is produced.
That is, in the electronic component module manufactured by the third conventional method, since the insulation between the semiconductor bear chip a and the electrode area d is made by the thermoplastic resin film i alone, as shown in FIG. 21A, if a high temperature load required in the workings such as laminate press and injection molding is applied on a packaged portion of the semiconductor bear chip a, the thermoplastic resin film i may be melted in some cases. In this state, if a high pressure is applied in a direction as indicated by the arrow in FIG. 21B, the electrode area d and the wiring board c are partly curved. Then, the semiconductor bear chip a is buried into the thermoplastic resin film i, resulting in a nonconformity that the semiconductor bear chip a and the electrode area d are contacted to cause a short-circuit.
[Document 1]
JP-A-6-243358
[Document 2]
JP-A-11-176022
[Document 3]
Japanese Patent No. 2586154
[Document 4]
JP-A-11-333409